Simultaneous strength optimization and recrystallization prevention in induction-heating-assisted laser additively manufactured Ni-based superalloys

Induction heating favors crack inhibition for laser additive manufacturing of Ni-based superalloys but may negatively influence columnar grain growth and mechanical properties. Here, by induction heating at a proper temperature during laser additive manufacturing, superalloys with a directionally solidified grain structure are obtained. Optimized γ′-precipitate size grants them higher microhardness than their counterparts either cast or additively manufactured without concurrent induction heating. Furthermore, lowered built-in dislocation density reduces the driving force for recrystallization. The combination of a maintained columnar grain structure, an increased microhardness, and a decreased risk of recrystallization offers a valuable pathway for advancing additive manufacturing of superalloys. Concurrent induction heating at a proper temperature benefits the laser additive manufacturing of Ni-based superalloys in terms of maintaining columnar grain structure, optimizing γ′ size, increasing mechanical hardness, and reducing risk of recrystallization.